The present invention relates to a shielded structure of a flat shielding electric wire for connecting a shield covering member of the flat shielding electric wire to a grounding conductor, and to a method of manufacturing the flat shielding electric wire.
The applicant proposed a related shielded structure of a flat shielding electric wire in which a shield covering member of the flat shielding electric wire sandwiched by a pair of resin members is electrically connected to a conductive wire of a grounding conductor by an ultrasonic horn. The related shielded structure will be described bellow.
As shown in FIG. 7, a flat shielding electric wire 100 is constituted by two shielding cores 103 having cores 101 covered with insulating inner casings 102 respectively and arranged in parallel, a shield covering member 104 of an electric conductor for covering the outer periphery of the two shielding cores 103 and having a contact portion 104a for a grounding conductor on the outside in the direction of the arrangement of the two shielding cores 103, a drain wire 105 provided in the contact portion 104a for the grounding conductor, and an insulating outer casing 106 for further covering the outer periphery of the shield covering member 104.
A pair of resin members 110 and 111 is provided with concave portions 110b and 111b almost corresponding to the outer sectional shapes of the shielding core 103 and the drain wire 105 in the flat shielding electric wire 100 with mutual bonding faces 110a and 111a butted against each other, respectively. Moreover, the mutual bonding faces 110a and 111a of the resin members 110 and 111 have flat faces 110c and 111c corresponding to a point to be set the contact portion 104a for a grounding conductor of the flat shielding electric wire 100 and a grounding conductor 113 for pressing the contact portion 104a for the grounding conductor and the grounding conductor 113 with the mutual bonding faces 110a and 111a butted against each other.
An ultrasonic horn 115 is constituted by a lower support base 115a and an ultrasonic horn body 115b provided just thereabove.
Next, a shielding procedure will be described. The lower resin member 111 is provided on the lower support base 115a of the ultrasonic horn 115. The flat shielding electric wire 100 is mounted on the lower resin member 111. One end side of the grounding conductor 113 is mounted thereon, and furthermore, the upper resin member 110 is put from thereabove. Thus, the flat shielding electric wire 100 is provided in each of the concave portions 110b and 111b of the resin members 110 and 111. The end side of the grounding conductor 113 is provided between the flat shielding electric wire 100 and the upper resin member 110, thereby bringing an ultrasonic excitation application set state.
In the ultrasonic excitation application set state, compression force is applied between the resin members 110 and 111, and a vibration is simultaneously applied by the ultrasonic horn 115. Consequently, the insulating outer casing 106 of the flat shielding electric wire 100 and an insulating outer casing 113b of the grounding conductor 113 are fused and scattered by the heat generation of a vibration energy so that a conductive wire 113a of the grounding conductor 113 comes in electrical contact with the contact portion 104a for the grounding conductor of the shield covering member 104 and the drain wire 105 in the flat shielding electric wire 100. Moreover, each of the contact portions of the bonding faces 110a and 111a of the resin members 110 and 111, the contact portion of the internal peripheral faces of the concave portions 110b and 111b of the resin members 110 and 111 and the insulating outer casing 106 of the flat shielding electric wire 100, and the contact portion of the insulating resin 113b of the grounding conductor 113 and the resin members 110 and 111 are fused by the heat generation of the vibration energy and the fused portions are solidified after the ultrasonic vibration is completely applied. Consequently, the resin members 110 and 111, the flat shielding electric wire 100 and the grounding conductor 113 are fixed to each other.
According to the related shielded structure, it is not necessary to peel the insulating outer casings 106 and 113b of the flat shielding electric wire 100 and the grounding conductor 113, and it is preferable that the lower resin member 111, the flat shielding electric wire 100, the grounding conductor 113 and the upper resin member 110 should be assembled in this order to give the ultrasonic vibration. Consequently, the number of steps for shielding is decreased, and a complicated manual work is not required and automation can also be achieved.
In the related shielded structure, however, when an ultrasonic wave is applied in the ultrasonic vibration application set state in which the flat shielding electric wire 100 and the grounding conductor 113 are set between the resin members 110 and 111, a phenomenon in which the grounding conductor 113 is moved in such a direction as to be repelled out of the resin members 110 and 111 by the ultrasonic vibration (a direction of an arrow a in FIG. 7) is generated (a cleaning effect). For this reason, a sufficient contact cannot be obtained between the grounding conductor 113, the contact portion 104a for the grounding conductor of the shield covering member 104 and drain wire 105 so that an electric connection performance is deteriorated.